The present invention relates to packaging machines in which a series of folding boxes fed one after another in a predetermined direction with a substantially constant center to center distance are processed in various stations and, more particularly, to a sealing strip applicator station for such a machine which is adjustable for processing different size boxes.
Principally, such a machine comprises an endless conveyor, such as a chain or a band running in the horizontal plane and provided with equally spaced carriers for folding boxes of cardboard or similar material. From a plane condition in a storage area, the folding boxes are fed to the conveyor and simultaneously erected into a substantially case-shaped configuration with top and bottom endwall flaps extending from the body portion of the folding box. In a conventional machine of this type the erected folding boxes are conveyed to the following stations: a transverse wall and longwall flap unfolding station, a sealing ribbon application and sealing station, a sealing ribbon cross-cutting station and a flap folding and sealing station. These stations are located along a rectilinearly extending portion of the conveyor and operate upon the bottom ends of the folding boxes. After the bottom sealing has been accomplished, at the end of the rectilinear portion the folding boxes are filled in a filling station, preferably situated along a curved portion of the conveyor, after which the folding boxes are conveyed along a second rectilinear portion in a direction opposite to that of the first rectilinear portion. With the exception of the transverse-wall and longwall flap unfolding station, the second rectilinear portion is provided with stations identical with those of said first portion, however with the difference that the latter operate upon the top ends of the folding boxes. At the end of the second rectilinear portion there is a discharge station for the filled and sealed folding boxes.
Basically, this machine is reliable and practical. However, it would be desirable to provide a sealing strip applicator wherein size adjustments within a maximally large size range may be made. With the known machine in such a case difficulties are encountered in the adaptation of the length of the sealing strip to be applied to the various folding boxes of different size.
It is therefore an object of this invention to provide a size adjustable sealing strip applicator.
A further object of this invention is to provide a sealing strip applicator wherein the sealing strip applied to each individual folding box is exactly the size which is necessary for the actual box size so that no waste material is generated.
Another object of this invention is to provide a reliable sealing of the sealing strip independent of the folding box size.